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Annotation of OpenXM_contrib/gmp/mpf/cmp.c, Revision 1.1.1.1

1.1       maekawa     1: /* mpf_cmp -- Compare two floats.
                      2:
                      3: Copyright (C) 1993, 1994, 1996 Free Software Foundation, Inc.
                      4:
                      5: This file is part of the GNU MP Library.
                      6:
                      7: The GNU MP Library is free software; you can redistribute it and/or modify
                      8: it under the terms of the GNU Library General Public License as published by
                      9: the Free Software Foundation; either version 2 of the License, or (at your
                     10: option) any later version.
                     11:
                     12: The GNU MP Library is distributed in the hope that it will be useful, but
                     13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
                     14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Library General Public License
                     18: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
                     19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     20: MA 02111-1307, USA. */
                     21:
                     22: #include "gmp.h"
                     23: #include "gmp-impl.h"
                     24:
                     25: int
                     26: #if __STDC__
                     27: mpf_cmp (mpf_srcptr u, mpf_srcptr v)
                     28: #else
                     29: mpf_cmp (u, v)
                     30:      mpf_srcptr u;
                     31:      mpf_srcptr v;
                     32: #endif
                     33: {
                     34:   mp_srcptr up, vp;
                     35:   mp_size_t usize, vsize;
                     36:   mp_exp_t uexp, vexp;
                     37:   int cmp;
                     38:   int usign;
                     39:
                     40:   uexp = u->_mp_exp;
                     41:   vexp = v->_mp_exp;
                     42:
                     43:   usize = u->_mp_size;
                     44:   vsize = v->_mp_size;
                     45:
                     46:   /* 1. Are the signs different?  */
                     47:   if ((usize ^ vsize) >= 0)
                     48:     {
                     49:       /* U and V are both non-negative or both negative.  */
                     50:       if (usize == 0)
                     51:        /* vsize >= 0 */
                     52:        return -(vsize != 0);
                     53:       if (vsize == 0)
                     54:        /* usize >= 0 */
                     55:        return usize != 0;
                     56:       /* Fall out.  */
                     57:     }
                     58:   else
                     59:     {
                     60:       /* Either U or V is negative, but not both.  */
                     61:       return usize >= 0 ? 1 : -1;
                     62:     }
                     63:
                     64:   /* U and V have the same sign and are both non-zero.  */
                     65:
                     66:   usign = usize >= 0 ? 1 : -1;
                     67:
                     68:   /* 2. Are the exponents different?  */
                     69:   if (uexp > vexp)
                     70:     return usign;
                     71:   if (uexp < vexp)
                     72:     return -usign;
                     73:
                     74:   usize = ABS (usize);
                     75:   vsize = ABS (vsize);
                     76:
                     77:   up = u->_mp_d;
                     78:   vp = v->_mp_d;
                     79:
                     80: #define STRICT_MPF_NORMALIZATION 0
                     81: #if ! STRICT_MPF_NORMALIZATION
                     82:   /* Ignore zeroes at the low end of U and V.  */
                     83:   while (up[0] == 0)
                     84:     {
                     85:       up++;
                     86:       usize--;
                     87:     }
                     88:   while (vp[0] == 0)
                     89:     {
                     90:       vp++;
                     91:       vsize--;
                     92:     }
                     93: #endif
                     94:
                     95:   if (usize > vsize)
                     96:     {
                     97:       cmp = mpn_cmp (up + usize - vsize, vp, vsize);
                     98:       if (cmp == 0)
                     99:        return usign;
                    100:     }
                    101:   else if (vsize > usize)
                    102:     {
                    103:       cmp = mpn_cmp (up, vp + vsize - usize, usize);
                    104:       if (cmp == 0)
                    105:        return -usign;
                    106:     }
                    107:   else
                    108:     {
                    109:       cmp = mpn_cmp (up, vp, usize);
                    110:       if (cmp == 0)
                    111:        return 0;
                    112:     }
                    113:   return cmp > 0 ? usign : -usign;
                    114: }